One particular shortcoming of the IEEE 802.16 family of (WiMAX) standards is a large percentage of bandwidth overhead for signaling, such as sending DL-MAP or UL-MAP messages. The signaling overhead is large, at least in part, because the DL-MAP and UL-MAP messages are encoded with a very conservative modulation coding scheme (MCS) in an effort to ensure that these messages are successfully decoded even by the mobile stations (MSs) located the greatest distance from a base station (BS) at cell boundaries.
The DL-MAP message may indicate system configuration parameters and the burst allocation information. The bandwidth inefficiency is especially significant in Voice over IP (VOIP) systems where a large number of users require large sized DL-MAP or UL-MAP messages. This signaling overhead may result in severely limited VOIP air-link capacity.